The effect of genetic robustness on evolvability in digital organisms

<p>Abstract</p> <p>Background</p> <p>Recent work has revealed that many biological systems keep functioning in the face of mutations and therefore can be considered genetically robust. However, several issues related to robustness remain poorly understood, such as its implications for evolvability (the ability to produce adaptive evolutionary innovations).</p> <p>Results</p> <p>Here, we use the Avida digital evolution platform to explore the effects of genetic robustness on evolvability. First, we obtained digital organisms with varying levels of robustness by evolving them under combinations of mutation rates and population sizes previously shown to select for different levels of robustness. Then, we assessed the ability of these organisms to adapt to novel environments in a variety of experimental conditions. The data consistently support that, for simple environments, genetic robustness fosters long-term evolvability, whereas, in the short-term, robustness is not beneficial for evolvability but may even be a counterproductive trait. For more complex environments, however, results are less conclusive.</p> <p>Conclusion</p> <p>The finding that the effect of robustness on evolvability is time-dependent is compatible with previous results obtained using RNA folding algorithms and transcriptional regulation models. A likely scenario is that, in the short-term, genetic robustness hampers evolvability because it reduces the intensity of selection, but that, in the long-term, relaxed selection facilitates the accumulation of genetic diversity and thus, promotes evolutionary innovation.</p

Fibrinogen Gamma Chain Promotes Aggregation of Vesicular Stomatitis Virus in Saliva

The spread of viruses among cells and hosts often involves multi-virion structures. For instance, virions can form aggregates that allow for the co-delivery of multiple genome copies to the same cell from a single infectious unit. Previously, we showed that vesicular stomatitis virus (VSV), an enveloped, negative-strand RNA virus, undergoes strong aggregation in the presence of saliva from certain individuals. However, the molecular components responsible for such aggregation remain unknown. Here we show that saliva-driven aggregation is protein dependent, and we use comparative proteomics to analyze the protein content of strongly versus poorly aggregating saliva. Quantitative analysis of over 300 proteins led to the identification of 18 upregulated proteins in strongly aggregating saliva. One of these proteins, the fibrinogen gamma chain, was verified experimentally as a factor promoting VSV aggregation in a dose-dependent manner. This study hence identifies a protein responsible for saliva-driven VSV aggregation. Yet, the possible involvement of additional proteins or factors cannot be discarded

Cooperative Virus-Virus Interactions: An Evolutionary Perspective

Despite extensive evidence of virus-virus interactions, not much is known about their biological significance. Importantly, virus-virus interactions could have evolved as a form of cooperation or simply be a by-product of other processes. Here, we review anddiscuss different types of virus-virus interactions from the point of view of social evolution, which provides a well-establishedframework for interpreting thefitness costs and benefits of such traits. We also classify interactions according to theirmechanisms of action and speculate on their evolutionary implications. As in any other biological system, the evolutionarystability of viral cooperation critically requires cheaters to be excluded from cooperative interactions. We discuss how cheaterviruses exploit cooperative traits and how viral populations are able to counteract this maladaptive process

Viroids: Survivors from the RNA World?

Because RNA can be a carrier of genetic information and a biocatalyst, there is a consensus that it emerged before DNA and proteins, which eventually assumed these roles and relegated RNA to intermediate functions. If such a scenario--the so-called RNA world--existed, we might hope to find its relics in our present world. The properties of viroids that make them candidates for being survivors of the RNA world include those expected for primitive RNA replicons: (a) small size imposed by error-prone replication, (b) high G + C content to increase replication fidelity, (c) circular structure for assuring complete replication without genomic tags, (d) structural periodicity for modular assembly into enlarged genomes, (e) lack of protein-coding ability consistent with a ribosome-free habitat, and (f) replication mediated in some by ribozymes, the fingerprint of the RNA world. With the advent of DNA and proteins, those protoviroids lost some abilities and became the plant parasites we now know.Peer reviewe

Topology testing of phylogenies using least squares methods

BACKGROUND: The least squares (LS) method for constructing confidence sets of trees is closely related to LS tree building methods, in which the goodness of fit of the distances measured on the tree (patristic distances) to the observed distances between taxa is the criterion used for selecting the best topology. The generalized LS (GLS) method for topology testing is often frustrated by the computational difficulties in calculating the covariance matrix and its inverse, which in practice requires approximations. The weighted LS (WLS) allows for a more efficient albeit approximate calculation of the test statistic by ignoring the covariances between the distances. RESULTS: The goal of this paper is to assess the applicability of the LS approach for constructing confidence sets of trees. We show that the approximations inherent to the WLS method did not affect negatively the accuracy and reliability of the test both in the analysis of biological sequences and DNA-DNA hybridization data (for which character-based testing methods cannot be used). On the other hand, we report several problems for the GLS method, at least for the available implementation. For many data sets of biological sequences, the GLS statistic could not be calculated. For some data sets for which it could, the GLS method included all the possible trees in the confidence set despite a strong phylogenetic signal in the data. Finally, contrary to WLS, for simulated sequences GLS showed undercoverage (frequent non-inclusion of the true tree in the confidence set). CONCLUSION: The WLS method provides a computationally efficient approximation to the GLS useful especially in exploratory analyses of confidence sets of trees, when assessing the phylogenetic signal in the data, and when other methods are not available

Turismo halal: análisis actual y perspectivas de un mercado emergente. Al Ándalus, el gigante dormido

Debido a su relevancia y complejidad, el turismo halal representa uno de los mayores desafíos para el sector turístico mundial, englobando a múltiples nacionalidades y particularidades basadas en preceptos del Islam. Un mercado emergente, que crece con fuerza gracias a la pujanza de la economía islámica, que reclama su sitio en el panorama mundial. El turista halal reclama destinos muslim friendly dentro de las diferentes tipologías turísticas, destacando el patrimonio cultural musulmán como uno de sus destinos más deseados, donde Al Ándalus y Andalucía ocupan una posición relevante dentro del imaginario musulmán. He aquí la importancia de promover el turismo halal en de nuestra Comunidad.Due to its importance and complexity, halal tourism represents one of the biggest challenges for the world tourism industry, encompassing multiple nationalities and characteristics based on precepts of Islam. As an emerging market, which thrives thanks to the strength of Islamic economics, halal tourism claims its place on the world in a different perspective to the west. For each tourist typology, the tourist claims for muslim friendly destinations, taking cultural heritage a clearly defined wish, where Al Ándalus and Andalusia take place an important position for the Muslims. Here we are how importance of promoting halal tourism within our Community is.Universidad de Sevilla. Máster en Dirección y Planificación del Turism

El proyecto de acto legislativo 192 de 2012 y el derecho internacional.

El proyecto de acto legislativo 192 de 2012  y el  derechointernacional

Barriers to scientific production of the female university teachers of the healt sciences áreas

To discover the features associated with personal and professional lives of university teachers, in the area of health sciences in the"Comunidad Valenciana" for the period 2003-2007, to learn if they contribute to a greater or lesser scientific productivity. Were interviewed in depth 30 teachers aged between 30 and 60 years in order to identify factors that hamper productivity. Have more difficulties to publish scientific papers, teachers less productive. Represent obstacles: the labor problems, the difficulty to obtain science projects and to publish in certain journals, to balance teaching and research, care work in hospitals, the maternity and children. Although the two groups of large and small producers point to the same problems in their work and personal life, are perceived more difficulties in the group of less productive. Most offer the same kind of solutions to reduce the gender distance

Vending machines: Food safety and quality assessment focused on food handlers and the variables involved in the industry

“NOTICE: this is the author’s version of a work that was accepted for publication in Food Control. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Food Control, 56, (October 2015)] DOI: 10.1016/j.foodcont.2015.01.052 " - http://www.sciencedirect.com/science/article/pii/S095671351500184X"The purpose of this paper was to analyse the quality and safety parameters of food products sold in vending machines. A hygienic-sanitary assessment was conducted on 338 vending machines located on the island of Gran Canaria. Hygiene Assessment System (HAS) surveys, food handler examinations and microbiological (processed food and water) and physicochemical (water) controls were applied, permitting evaluation through the identification of the main risks and/or hazards of the hygienic-sanitary quality of the products sold in vending machines. Despite the positive results obtained from the HAS surveys applied to all the vending machines, achieving a total mean score of 87.6 ± 7.5 out of 100, the microbiological analysis showed that 5.7% of the 105 food samples were contaminated with Listeria monocytogenes, while Salmonella spp., Escherichia coli and Staphylococcus aureus were below the legally permitted limits. The lack of vehicles able to transport perishable food at correct temperatures (<8 °C) and the fact that some refrigerated vending machines were not at an ideal cooling temperature may have contributed to these values. The assessment tools used in this study revealed hygienic deficiencies in the transportation and microbiological quality of the products, despite the favourable results obtained in the HAS surveys and food handler examinations, indicating that this relationship should be the subject of further study to improve its usefulness in the field of Hazard Analysis and Critical Control Points.